Radio signaling



Jan. 3, 1939. J. A. SPENCER ET Al.

RADIO S IGNALING Filed Aug. l5, 1936 III.' i

A'AAAAA nAAA A AAAAAA INVENTORS JAMES A. SPENCER AND RICHARD E. MATHESBY Wg ATTORNEY Patented Jan. 3, 1939 t n UNITED STATES PATENT OFFiCERADIO SIGNALING James A. Spencer, Teaneck, and Richard E.

Mathes, Westfield, N. J., assignors to Radio Corporation of America, acorporation of Delaware Application August 15, 1936, Serial No. 96,162

4 Claims. (Cl. 250-8) This invention relates to radia relaying and Theplate current of tube 26 flowing through coil receiving systems. 40opens the contacts 42 of polar-relay 46, 42, 44,

One object of this invention is toy provide a in turn breaking thecircuit through the comradio relaying system employingprinten-transbined printer-transmitter apparatus 46, which is mitterapparatus in which received radio Waves normally supplied with operatingcurrent from 5 are utilized to actuate the printer apparatus withthelead 48. out affecting closely associated transmitter ap- In thepresence of a signal upon antenna A, paratus. A further object is toprovide a'circuit the resulting tone passed on to the rectifier tubearrangement having impedance balanced 6 cuts off current to the anode I6of the rectifierbranches associated with a demodulating system amplifiertube6. The blocking of tube 6 cuts off 10 for ultra short waves, whichbalanced circuit arcurrent flow through the resistors i2, I4 wherebyrangement is effective to actuate printer mechathe' 'grid 20 of tube 24is at ground potential. nism, but during such actuation is ineffectiveto However, since current is flowing through reoperate a closelyassociated transmitting device. sistance 32, the cathode V50 of tube 24is at such It is a further object, however, to arrange this a positivepotential with respect to ground that transmitting device so that it maybe utilized at tube 24 blocks. This action raises the potential timesfor transmitting an independent signal to of grid 34 with respect to itscathode 38 of tube 'another receiver in the relay system. 36, causingcurrent ow through tube 36 and Further objects, advantages and features0f the hence through coil 44. Simultaneously, while this 12o presentinvention will be apparent from a Conaction is going on, tube 2S blocksfor the reason 20 sideration of the accompanying drawing, taken thatcurrent flow through the resistors 3a, 32 has together with thefollowing more detailed specifisimultaneously held the potential ofcathode 52 cation. at positive potential with respect to ground, cut-The accompanying drawing illustrates in wirting off tube 26.

a5 ing diagram form a preferred modification of our Cessation of currentflow through coil 40 and 25 radio receiving and retransmitting system.actuating current flow through coil 44 thereupon Turning to the drawing,modulated short Wave closes contacts4 42 and permits current to flo-Wsignals received upon antenna A are fed into a through the printermechanism 48. In this way, radio receiver RR whose detected output isfed the printer 46 is actuated by the incoming signals 3o into a tonefilter TF. The received tones are fed received upon antenna A withoutaffecting in any 30 through a transformer T into a vacuum tube way thetransmitting contact TC. The reason amplifier VA. The output of theamplier is fed for this is that the contacts TC are the contacts to aSecond transformer T2 aCTOSS the plates 2, 4 of a polar-relay havingimpedance-balanced coil of a combined amplier-detector tube 6. T0sections 54, 56 through which current changes smooth out the rectifiedtone, a lter F, consisting equally when contacts 42 are opened andclosed. 35 of a resistance and condenser in-parallel, is pro- Equalchanges through the coil sections 54, 56 vided. The Output 0f theI'eCtieI iS then imdo not affect the transmitting contacts TC. pressedupon the grid 8. as indicated. Causing However, when the transmittingcontacts TC amplied, rectified current to flow to the plate l0 areopened and closed, and the transmitter sec- 0f the Combined detector,direct current amplifier tion of the apparatus 46 is actuated, thecathodes 40 tube 6. This amplied Current flows through the 5s, 6o oftubes 62, 64 are combined in potential resistors l2, I4 which form aseries connection With respect to the grids of tubes 62, 34 which, asbetween the Cathode I6 0f tube 6 and groundindicated, are maintained atground potential In the absence 0f Slgnal Current passes t0 plate andsupplied with tone from a tone transformer m of tube E Since the grid 3is at the potential of 66. With the contacts TC closed the cathodes 45cathode I6. Consequently, current flows to the assume such potentialwith respct to ground plate 'o and through resistors l2 m' AS a conse'that tone fed into transformer 66 reappears in queme the Control grlds2e 22 of tubes 24 25 amplied form in the output transformer 68.

become positive and both tubes 24, 26 pass plate 5o Current PlateCurrent flow through tube 24 Th1s tone is then fed through a iilter 'lllto moduows through resistors 28, 30 and 32, thereby im late wavesgenerated in a radio transmitter 12, pressing a negative potential onthe grid 34 of Whlch modulated waves are then radiated over tube sa withrespect to the Cathode 3s of that the transmitting antenna TA to anySuitable tube. As a result of this action, plate current TeCeVngStatiOIl. 55 flows through tube 26, whereas tube 36 is cut 01T. When thecontacts TC' are open, cathodes 58, 55

60 of tubes 62, 64 assume a relatively high positive potential withrespect to ground, as a consequence of which tubes 62, 64 block and notone is impressed upon the radio transmitter 12.

The printer-transmitter 4B is preferably of the type known to the art asthe Teletype model I4.

It is to be noted that the printer-transmitter apparatus 46 may beconnected at some distant point through the intermediary of a suitablelandline (not shown) in which case separate positive supply voltages maybe supplied at the points marked Y, Y. It is to be understood that thissystem may be used as part of a radio repeating system or as a linkbetween a radio receiving station and a landline system, it being notedthat the printer-transmitter apparatus 46 may be replaced by severalprinter transmitters connected in series.

Power supply for the various tubes involved may be derived from thepower supply circuits PS which are believed to be self-explanatory, itbeing noted that the heaters of the various tubes are connected to thepoints marked X, X.

For transmitting purposes, the tone filtered through lter 'l0 may berectified and used to key the transmitter 'l2 or it may be used to tonemodulate radio waves generated at the transmitter 12.

What is claimed is:

1. In combination, means for receiving a keyed and tone-modulated codesignal, means for demodulating the signal so as to obtain the keyedmarking and spacing components thereof, a pushpull circuit operableunder control of the keyed components of said signals, a polarized relaysymmetrically disposed in said push-pull circuit, a circuit havingimpedance-balanced branches and including the coils of a secondpolarized relay and contacts operativebythe rst said relay,transmittingcontacts operable by the second said relay, a telegraph printer andkeyerinone of said branches, radio transmitting apparatus connected to saidtransmitting contacts, and means including further circuit arrangementssuch that said telegraph printer is caused to respond to code signals asreceived, demodulated, and impressed upon both of said relays, whilesaid transmitting contacts remain undisturbed, and said radiotransmitting apparatus is caused to respond only to keying operationsinitiated by said telegraph keyer for sending code signals through saidsecond relay and the transmitting contacts thereof.

2. Radio telegraph apparatus comprising separate transmitting andreceiving channels and a. telegraph instrument having a receiving andkeying circuit common to both channels, in combination with meansincluding a. push-pull electron tube circuit responsive to received codesignals for causing said instrument to record the intelligence Aof saidcode signals while maintaining said transmitting channel idle, and meansincluding a polarized relay in a circuit having impedance-balancedbranches, one of which contains said instrument for causing code signalsto be sent out over said transmitting channel under control of saidinstrument.

3. Apparatus in accordance with claim 2 and including means fordemodulating the received code signals when they consist oftone-modulated signaling elements, and means for applying tonemodulation to the transmitted signals when they are keyed by saidtelegraph instrument.

4. Radio telegraph apparatus comprising separate transmitting andreceiving channels and a typewriting telegraph unit having a receivingand keying circuit common to both channels, in combination with a tonefrequency potential source, a push-pull amplifier the bias of which isadapted to be varied by keying from full cut-off to a normal amplifyingcondition thereby to transmit code signals modulated by said tonesource, an electro-magnetic relay operable by said typewriting telegraphunit to control the bias on said amplifier, and means including apolarized relay under control of received code signals for renderingsaid typewriting telegraph unit responsive without influencing saidamplier and its associated transmitting channel.

RICHARD E. MATHES. JAMES A. SPENCER.

